What was found in Preston's water
The level at the city's main supplier, the highest level anywhere in the city, the EPA limit for each, and where every figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Nitrate-Nitrite | 2625 µg/L 26% of the EPA limit 10000 µg/L Main supplier: NORWICH PUBLIC UTILITIES · 36,163 people · 2019 | 3/3 | SYR4 |
| Nitrate | 2470 µg/L 25% of the EPA limit 10000 µg/L Main supplier: NORWICH PUBLIC UTILITIES · 36,163 people · 2019
Highest in the city: 2480 µg/L — LINCOLN PARK ELDERLY HOUSING · 80 people · 2019 | 3/3 | SYR4 |
| Fluoride | 992 µg/L 25% of the EPA limit 4000 µg/L Main supplier: NORWICH PUBLIC UTILITIES · 36,163 people · 2019 | 2/3 | SYR4 |
| Nitrite | 860 µg/L 86% of the EPA limit 1000 µg/L Main supplier: NORWICH PUBLIC UTILITIES · 36,163 people · 2019 | 1/3 | SYR4 |
| Copper | 107.5 µg/L 8.3% of the EPA limit 1300 µg/L Main supplier: NORWICH PUBLIC UTILITIES · 36,163 people · 2019
Highest in the city: 795.9 µg/L — LINCOLN PARK ELDERLY HOUSING · 80 people · 2019 | 3/3 | SYR4 |
| TTHM | 115.47 µg/L 144% of the EPA limit, at the 95th percentile of samples — 80 µg/L Main supplier: NORWICH PUBLIC UTILITIES · 36,163 people · 2019 | 1/3 | SYR4 |
| Total Haloacetic Acids (HAA5) | 66.4 µg/L 111% of the EPA limit, at the 95th percentile of samples — 60 µg/L Main supplier: NORWICH PUBLIC UTILITIES · 36,163 people · 2019 | 1/3 | SYR4 |
| Chloroform | 50.5 µg/L No EPA limit set Main supplier: NORWICH PUBLIC UTILITIES · 36,163 people · 2019 | 1/3 | SYR4 |
| Barium | 11 µg/L 0.5% of the EPA limit 2000 µg/L Main supplier: NORWICH PUBLIC UTILITIES · 36,163 people · 2019
Highest in the city: 29.9 µg/L — LINCOLN PARK ELDERLY HOUSING · 80 people · 2018 | 3/3 | SYR4 |
| Lead | 17.6 µg/L 117% of the EPA limit, at the 95th percentile of samples — 15 µg/L Main supplier: NORWICH PUBLIC UTILITIES · 36,163 people · 2019 | 3/3 | SYR4 |
| Bromodichloromethane | 7.65 µg/L No EPA limit set Main supplier: NORWICH PUBLIC UTILITIES · 36,163 people · 2019 | 1/3 | SYR4 |
| Selenium | 2.6 µg/L 5.2% of the EPA limit 50 µg/L Main supplier: NORWICH PUBLIC UTILITIES · 36,163 people · 2019 | 1/3 | SYR4 |
| Arsenic | 2.27 µg/L 23% of the EPA limit 10 µg/L Highest in the city: PRESTON PLAINS WATER COMPANY · 550 people · 2018 | 1/3 | SYR4 |
| Combined Uranium | 2.065 µg/L 6.9% of the EPA limit 30 µg/L Highest in the city: PRESTON PLAINS WATER COMPANY · 550 people · 2018 | 2/3 | SYR4 |
| Combined Radium (-226 And -228) | 1.09 pCi/L 22% of the EPA limit 5 pCi/L Main supplier: NORWICH PUBLIC UTILITIES · 36,163 people · 2017 | 1/3 | SYR4 |
| Dibromochloromethane | 0.8725 µg/L No EPA limit set Main supplier: NORWICH PUBLIC UTILITIES · 36,163 people · 2019 | 1/3 | SYR4 |
| Beryllium, Total | 0.2000 µg/L 5% of the EPA limit 4 µg/L Highest in the city: LINCOLN PARK ELDERLY HOUSING · 80 people · 2018 | 1/3 | SYR4 |
| PFOS | 0.0162 µg/L No EPA limit set Main supplier: NORWICH PUBLIC UTILITIES · 36,163 people · 2024 | 1/3 | UCMR-5 |
| PFHXS | 0.0125 µg/L No EPA limit set Main supplier: NORWICH PUBLIC UTILITIES · 36,163 people · 2024 | 1/3 | UCMR-5 |
| PFOA | 0.0067 µg/L No EPA limit set Main supplier: NORWICH PUBLIC UTILITIES · 36,163 people · 2024 | 1/3 | UCMR-5 |
| PFBS | 0.0060 µg/L No EPA limit set Main supplier: NORWICH PUBLIC UTILITIES · 36,163 people · 2024 | 1/3 | UCMR-5 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: NORWICH PUBLIC UTILITIES · 36,163 people · 2025
Highest in the city: 0.0053 mg/L — PRESTON PLAINS WATER COMPANY · 550 people · 2024 | 3/3 | LCR |
| Pfpea | 0.0039 µg/L No EPA limit set Main supplier: NORWICH PUBLIC UTILITIES · 36,163 people · 2024 | 1/3 | UCMR-5 |
Each bar shows the measured level as a share of the EPA limit: green is
well under, amber is close to it, red is over. For lead and copper the
limit applies to exactly the 90th-percentile figure shown, so red there
means a real exceedance. For everything else the limit applies to a
running annual average while the figure is the 95th percentile of the
system's samples — over 100% is worth reading, but is not by itself a
violation.
Formal violations are listed separately.
These are the utilities' own EPA-reported results, not a city-wide
average. A detection means the lab measured the
substance — it isn't the same as exceeding a legal limit. Hover a source
tag to see the EPA program and years behind each figure.
Water suppliers serving Preston
| Supplier | Population served |
|---|---|
| NORWICH PUBLIC UTILITIES | 36,163 |
| PRESTON PLAINS WATER COMPANY | 550 |
| LINCOLN PARK ELDERLY HOUSING | 80 |
Frequently asked questions about Preston tap water
Is Preston tap water safe to drink?
EPA testing detected 23 contaminants in the water serving Preston. A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.
How many water suppliers serve Preston?
3 public water suppliers report drinking-water monitoring for Preston, Connecticut to the EPA. Each is listed above with its population served.
What contaminants are in Preston's water?
The contaminants EPA monitoring detected in Preston include Nitrate-Nitrite, Nitrate, Fluoride, Nitrite, Copper. The full list, with the level at the main supplier and the data source, is in the table above.
Where does this data come from?
Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.